1. Field of the Invention
This invention relates to a drilling device and process, and is more particularly concerned with an hydraulically controlled drilling rig which is designed to be mounted onto various types of vehicles, and the process of using the same.
2. Description of the Prior Art
Hydraulically controlled drilling rigs are generally well known in the art, and have traditionally utilized similar structures within the various types of drills. The Acker Company of Scranton, Pa., has manufactured several various types of drill rigs, which rigs exemplify features that have not been significantly modified since the early part of this century. For example, the Acker ADII typifies one of the most commonly used drill rigs, employing features that are quite well known. This type of drill rig incorporates a derrick which supports two, parallel hydraulic cylinder feed assemblies. These feed assemblies raise and lower an exposed drill head by simultaneously applying force in the same direction to both the left side and right side of a support frame, which is integrally attached to the drill head. Because two feed assemblies are used in this manner, the drill head could be subjected to a turning force, perpendicular to the direction the drill head is moving, if the support frame was not incorporated to react the force provided by the two cylinders. Using two feed assemblies instead of one adds to the overall weight of the drill rig. This undesirable effect is augmented by the fact that the support frame for the rotary assembly is also required. Further, this twin feed assembly design, which incorporates redundant structure, necessitates a substantial support structure that requires a heavy, sliding base for movement onto on and off-hole positions. This structure requires that the drill rig be mounted on a large vehicle, which limits the rig's versatility. This drill rig additionally is designed to be used in vertical applications, only. Another critical limitation of this type of drill rig is that this design requires a heavy, square shaft, or Kelly bar, which acts as a drive shaft. This shaft is exposed and, therefore, is a safety hazard, and further adds to the weight of the device. Further, because the drill head slides on the outside of the feed cylinders, the drill rods are contained between the base supports for the feed cylinders. When the head is in a raised position, the distance between the base supports limits the size of the auger which can be driven by the device. Additionally, because of the arrangement of the hydraulic support jacks, the control panel for the rig cannot be placed along the rear of the rig at a safe distance from the rotating elements.
The Acker Core-Max drill rig utilizes a large, folding derrick which is raised and lowered by two double-acting hydraulic cylinders. The drive head is releasably mounted to a movable carriage that is slidably engaged with a mast mounted within the derrick. The feed cylinder is also mounted within the derrick in parallel, eccentric relationship to the drill rods, rather in direct, concentric alignment. Since the feed cylinder is not concentric with the drill rods, a bending moment results with respect to the force applied to the moving carriage. This results in less efficient application of force, and wear on the carriage and mast assemblies. This arrangement also requires a large amount of structural steel and, therefore, is a comparatively heavy rig with numerous parts. The rotation elements of the rotary assembly are also mostly exposed, providing a safety hazard.
The Acker Mountaineer drill rig incorporates many of the same features utilized by both devices previously discussed, including the dual, parallel feed assemblies, the large derrick, exposed rotating elements, control panel position close to the moving parts, and the heavy sliding base. Consequently, this design also has many of the same limitations referenced above.
The Acker Soil Sentry drill rig is an example of a relatively lightweight drill rig, however, it includes limitations such as feed assembly eccentric to the drill rods, support frame required to react the force applied by the feed assembly, exposed rotating parts, and limited performance characteristics which limit its applications.